Me and my wife has recently got a male 9 weeks old kitten. It comes from a good house, so it's already been treated for fleas and (most importantly) litter trained. According to its old owner, it used to eat pretty much any brand of wet and dry food.

However, the first days we had it it refused to eat anything at all we gave it. It didn't seem stressed or scared, just refused to eat even though it was begging for food. Then I tried putting some canned tuna in his wet food and, lo and behold, it ate the whole lot in a jiffy. In the meantime we also managed to find a brand of dry food it eats, so now he has that too.

Now, I know that you shouldn't feed a cat just canned tuna because of mercury accumulation and supplement deficiency, but the latter shouldn't be a problem as it's mixed with regular cat food. So, my question is:

How much canned tuna can a cat eat per day? We're using Lidl (UK) branded tuna in spring water, Here's some pictures of ingredients and nutritional values. It eats approx. between 10g and 15g of tuna per day (I've actually weighted it).

I don't mind adding tuna to its food for the rest of its life, as long as it's safe for it. Thank you.

  • You could also try canned chicken as an alternative to tuna (the "chicken of the sea" :P). I've fostered many cats & kittens who've all loved it. – brhans Jun 26 '18 at 16:39
  • @brhans Sorry, but I've never seen canned chicken here in the UK, I didn't even know that was a thing. Where can I find it? – vale.maio2 Jun 26 '18 at 17:30
  • @JamesJenkins I've already seen this post, I just thought mine was a (slightly) different question. – vale.maio2 Jun 26 '18 at 17:34
  • Hmmm ... good point - after living in the US for a few years I tend to take for granted some of the stuff I can buy ... Sainsbury's and Tesco both list canned/tinned cured chicken, but I'm not sure if it's the same as what I get over here from Walmart, BJ's, etc. (which is almost indistinguishable from tuna in brine). – brhans Jun 26 '18 at 17:44
  • @brhans oh, canned chicken for cats! I thought you meant proper canned chicken for human consumption (which reminds me of an Ashens' video on Youtube, but now I'm digressing...). Is this what you're talking about? – vale.maio2 Jun 26 '18 at 21:37

Mercury is a cumulative poison, meaning that if you eat it even in small amounts but on a regular basis, it will build up and cause harm. As a result, generally speaking, the higher up in the food chain the fish is, the more mercury its likely to have because it accumulates it from the prey its eaten. Tuna are top predators, and as such, canned tuna is particularly bad for mercury. The FDA recommends at most one serving of canned tuna (8 to 12 ounces) for a HUMAN once a week for this reason. https://www.epa.gov/fish-tech/epa-fda-fish-advice-technical-information

Doing the math, what you're feeding your cat is at the higher end, as much as about 3.5 ounces a week. Cats being so much smaller than humans, I can only conclude then what you're currently feeding your cat is probably too much in the long term.

My suggestion is to cut out the tuna entirely. If your cat is still being reluctant to eat the cat food, make this transistion gradually over the period of a few days. Add less and less tuna each day until the cat accepts the regular food. If that doesn't work, you may have to accept the cat will only eat the kibble.

  • Thank you for your answer, I appreciate it. There's something that I still don't get: take this cat food as an example. It states that it has a 4% content of tuna which, if I'm not mistaken, gives a 4g per pouch (each pouch is 100g). Feeding 2 to 3 pouches a day means around 8g to 12g of tuna a day, not so different from what I'm currently doing. Am I missing something? I'm not trying to be right at all cost, I just can't see the difference between that tuna and canned tuna. – vale.maio2 Jun 26 '18 at 17:45
  • I can't really answer that for sure, but possible explanations I can think of is that the catfood version is made with a different variety of tuna that usually contains less mercury (even among the tuna used for human consumption has different amounts depending on the exact species), or perhaps like the human food, it's not intended to be eaten by your cat as a daily meal. – Kai Jun 26 '18 at 21:42

Not the answer you're looking for? Browse other questions tagged or ask your own question.